Vehicle navigation, collision avoidance and control system

ABSTRACT

A collision warning and avoidance system which comprising an integrated on-board Train Navigation Unit ( 3 ) and a GPS Interface Subsystem to locate a train. The system includes a GPS ( 2 ) location signal, at least one fixed transponder station ( 31 ) and a calibrated, rectified transponder identification subsystem for scanning the track based transponders for override of train controls in the event of a collision risk and further comprising a database of all transponders, their location and the track ID on which they are located. Data and information are computer processed and analysed in neural networks in one train to identify, rank, and evaluate collision hazards.

This application is a 371 U.S. national stage application ofinternational application PCT/AU03/00342 filed on Mar. 21, 2003, whichclaims priority of Australian patent application PS 1237 filed on Mar.22, 2002.

BACKGROUND

The present invention relates to vehicle safety and more particularlyrelates to an identification system capable of vehicle collision warningand avoidance and More particularly the invention relates to collisionavoidance systems for track networks including means to allow vehicleand track identification. More particularly the present inventionrelates to anticipatory detection and transmission of a vehicle locationin a network for the purpose of avoidance of a collision between two ormore vehicles in the network. Although the invention to be describedherein is adaptable to a variety of vehicle networks, it will primarilybe described with reference to its application to rail cars in railnetworks.

PRIOR ART

There are in existence a variety of vehicle collision avoidance systemsfor both road and rail traffic. The complete disclosure of the followingpatents is incorporated by reference herein in their entirety.

U.S. Pat. No. 5,272,483 to Kato describes an automobile navigationsystem. This invention attempts to correct inaccuracies in the GPSsystem through the use of an inertial guidance, geomagnetic sensor, orvehicle crank shaft speed sensor.

U.S. Pat. Nos. 5,314,037 and 5,529,138 to Shaw et al. describe acollision avoidance system using laser radar and a laser gyroscope. Thefollowing paragraphs are quoted from U.S. Pat. No. 5,314,037 thatprovides a background to collision avoidance prior art. “The use ofradars in collision avoidance systems is generally known. U.S. Pat. No.4,403,220 which discloses a radar system adapted to detect relativeheadings between aircraft or ships at sea and a detected object movingrelative to the ground. The system is adapted to a collision avoidanceapplication. U.S. Pat. No. 4,072,945 dated Feb. 7, 1978 discloses aradar operated collision avoidance system for roadway vehicles. Thesystem senses the vehicle speed relative to an object and its distanceand decides whether the vehicle is approaching the object at adangerously high speed. A minimum allowable distance represented by adigital code is stored in a memory of a computer and the minimumallowable distance is compared with the distance sensed by the radar.”

Many of the prior art collision avoidance systems use microwave radarsas a ranging and detecting device. There are multiple disadvantages ofthese automobile collision avoidance systems when microwave radars areused. One major disadvantage is related to the beam width, that is theangular width of the main lobe of the radar, and the associated angularresolution of the microwave radar. The beam width is inverselyproportional to the antenna diameter in wavelength. With the limitationof the antenna size, it is very difficult to make a reasonable sizemicrowave radar with beam width less than 3 degrees. At the desiredscanning distance, this beam width will scan an area that is much toobig and thus is too nonspecific and difficult to differentiate thereceived echoes. Besides getting echo from another car in front of it,this radar will also receive echoes from roadside signs, trees or posts,or bridges overpassing an expressway. On highways with divided lanes themicrowave radar will receive echoes from cars 2 or 3 lanes away and hasdifficulty to in differentiating them from echoes coming from objects inthe same lane. Because of the poor angular resolution of microwaveradars, the direction of objects cannot be specifically determined andobjects too close to one another cannot be separated. The angularresolution of microwave radars is not small enough for them to beeffectively used to monitor roadway traffic. The other disadvantage isthat the microwave radars have difficulty in distinguishing radarsignals coming from adjacent cars with similar equipment. If there aremore than two cars with the same radar equipment on the same scene, thesignals become very confusing.

In the Shaw invention laser radars are used as scanning and rangingdevices. These laser radar devices have much smaller beam and angularresolution and give more specific and precise information of thedetected object's direction and distance.

Radars have been used widely in detection of speed and distance ofmoving objects. Most radars use electromagnetic waves in the microwavefrequency range. They are divided into pulse radars and continuousradars. In a pulse radar, the transmitter sends out radar signalsthrough the antenna in pulses with extremely short duration, millionthof a second for example. The next pulse is emitted after the echoes havebeen received. The radars use Doppler principle to calculate the speedby the amount of frequency shift. The angular resolution of a radardepends on the beam width. If two targets are at about the same distancebut at slightly different angles, they can be separated if they are morethan one beam width apart. Laser light is highly directional. The laserlight travels as a parallel beam and spreads very little. It can travelin very narrow beams. In comparison to microwave, laser light has higherfrequency and shorter wavelength. Laser light can be used to measurespeed and distance in the same way as the microwave radar.

The laser beams are highly directional. The laser receiving equipmentare also highly directional. Since the laser receiving equipment willreceive only the laser beams aimed at it, most interference can beavoided. This is an important advantage over the microwave radar. Whenthere are multiple cars with the same laser radars at the same scene,their reflected signals will not interfere with each other. Confusioncan be easily avoided.

The laser gyroscope is the modern type of gyroscope with higher degreeof accuracy, cheaper and much smaller than the traditional mechanicalgyroscope. It can give directional information precisely. A typicallaser gyroscope is made of glass-like material and is shaped like atriangle or a rectangle. A laser beam is generated and split into twoparts that travel in opposite directions around the triangle orrectangle. Laser gyroscope has been used by airlines as automatic pilotsto keep the airplanes on course. If the aircraft moves off course, themovement to one side will make one laser beam travel further than theother. Computer can analyze how much the laser beams are out of step andcompute the plane's change in direction. Therefore, laser gyroscope cansense the rotation rate or direction change rate accurately.

Laser lights do not penetrate rain, sandstorm, fog or snow, etc. as wellas microwave radar. However, infrared light will penetrate rain,sandstorm, fog or snow better than the visible light. Therefore, therain or snow, etc. will affect the driver's vision much more than theyaffect the infrared laser radar. If the rain or snow etc. are heavyenough, they may reduce the effective range of the laser radar. Withhighly directional character and with very small beam width, laserradars have other advantages as compared with microwave radars.

The receiver of the laser radar is aimed at exactly the same directionas the associated transmitter. The receiver is also highly directional.The receiver will not receive the reflected back laser light emittedfrom other transmitters on the same vehicle or from transmitters onadjacent vehicles because ordinarily the other laser light reflectionwill come in a direction different from the receivers direction, withthe following two very rare and brief exceptions. The first exception isthat confusion may occur when an oncoming vehicle's laser beam happen toaim at the system-equipped vehicle's receiver. In two moving cars thissituation will last at most only a minimal fraction of a second. Asecond exception is that confusion may occur when an adjacent vehicle'slaser beam happens to illuminate at the same spot as the spotilluminated by the system-equipped vehicle's laser beam. Then thereflected laser light from the adjacent vehicle may come in the rightdirection for the system-equipped vehicle's receiver.

Shaw, in these patents, relies on two laser radar systems in order toget an accurate prediction of the location of the vehicle on the roadwayusing triangulation. No image of vehicles or other objects on theroadway is formed. No attempt is made to identify the illuminatedobject. Shaw uses triangulation from two laser radars to obtain therelative velocity of the object being interrogated.

U.S. Pat. No. 5,367,463 to Tsuji describes a vehicle azimuth determiningsystem. It uses regression lines to find vehicle on map when there areerrors in the GPS and map data. The advantage of this invention is thatit shows a method of combining both map matching data and GPS along witha gyro and a vehicle velocity and odometer data to improve the overalllocation accuracy of the vehicle.

U.S. Pat. No. 5,383,127 to Shibata uses map matching algorithms tocorrect for errors in the GPS navigational system to provide a moreaccurate indication of where the vehicle is or, in particular, on whatroad the vehicle is. The main purpose of the system is for navigationand, in particular, in determining the road on which the vehicle istraveling.

U.S. Pat. No. 5,416,712 to Geier, et al. relates generally to navigationsystems and more specifically to global positioning systems that usedead reckoning apparatus to fill in as backup during periods of GPSshadowing such as occur amongst obstacles, e.g., tall buildings in largecities.

U.S. Pat. No. 5,463,384 to Juds uses a plurality of infrared beams toalert a truck driver that a vehicle is in his blind spot when he beginsto turn the vehicle. The system is typically activated by the vehicle'sturn signal. No attempt is made to measure exactly where the object is,only whether it is in the blind spot or not. U.S. Pat. No. 5,467,072 toMichael relates to a phased array radar system that permits the steeringof a radar beam without having to rotate antennas. Aside from that, itsuffers from all the disadvantages of radar systems as described above.In particular, it is not capable of giving accurate three-dimensionalmeasurements of an object on the roadway.

U.S. Pat. No. 5,479,173 to Yoshioka, et al. uses a steering anglesensor, a yaw rate sensor and a velocity of the vehicle sensor topredict the path that the vehicle will take. It uses a radar unit toidentify various obstacles that may be in the path of the vehicle, andit uses a CCD camera to try to determine that the road is changingdirection in front of the vehicle. No mention is made of the accuracywith which these determinations are made. It is unlikely that sub-meteraccuracy is achieved. U.S. Pat. No. 5,486,832 to Hulderman employsmillimeter wave radar and optical techniques to eliminate the need for amechanical scanning system.

U.S. Pat. No. 5,504,482 to Schreder discloses an automobile equippedwith an inertial and satellite navigation system as well as a local areadigitized street map. The main use of this patent is for route guidancein the presence of traffic jams, etc. This patent describes howinformation as to the state of the traffic on a highway can betransmitted and utilized by a properly equipped vehicle to change theroute the driver would take in going to his destination. Nevertheless,this patent provides a good picture of the state of the art as can beseen from the following quoted paragraphs:

There are in existence sytems which improve vehicular control andincrease safety associated with the common automobile usage. Forexample, it is known that gyro based inertial navigation systems havebeen used to generate three-dimensional position information, includingaccurate acceleration and velocity information over a relatively shorttravel distance, and that GPS satellite positioning systems can providethree-dimensional vehicular positioning. The prior art has failed tointegrate some of the known technologies in a comprehensive fashion toprovide a complete collision warning and avoidance system.

GPS satellite reception has been used in intelligent vehicle highwaysystems to enhance vehicular tracking on digitized road maps as part ofa guidance and control system. These systems use GPS to determine whendrift errors become excessive and to indicate that recalibration isnecessary. However, the GPS reception is not to the best of theapplicant's knowledge used for automatic accurate recalibration ofcurrent vehicular positioning.

These Intelligent Vehicle Highway Systems use the compass and wheelsensors for vehicular positioning for route guidance, but do not useaccurate GPS and inertial route navigation and guidance and do not useinertial measuring units for dynamic vehicular control. Even thoughdynamic electronic vehicular control, for example, anti-lock braking,anti-skid steering, and electronic control suspension have beencontemplated, these systems do not functionally integrate these dynamiccontrols with an accurate inertial route guidance system having aninertial measuring unit well suited for dynamic motion sensing.

There remains a long felt want to provide an integrated vehiclecollision warning system which allows an operator of one vehicle to knowthe specific location of at least one other vehicle in its vicinity tothereby allow collision warning in the event that vehicles are on acollision course.

A known system for preventing vehicle accidents, provides positiondetermining means for determining the absolute position of a firstvehicle. The position determining means comprises a receiver arranged inthe first vehicle and structured and arranged to receive position datafrom a GPS satellite network and receive wide-area differential GPScorrection data. The system also includes a memory for storing datarelating to edges of roadways on which the first vehicle may travel. Aprocessor is coupled to the determining means and the memory forcomparing the absolute position of the first vehicle as determined uponthe reception of the position data from the satellite network andwide-area differential GPS correction data by the receiver to the edgesof the roadway in order to determine the location of the first vehiclerelative to the edges of the roadway reaction means coupled to theprocessor for affecting a system on the first vehicle when the locationof the first vehicle approaches close to an edge of the roadway orintersects with an edge of the roadway. This system also includes acommunication device arranged in the first vehicle and coupled to theprocessing means for receiving a communication of data including atleast one of the size, type, mass and orientation of other vehicles,said processing means being structured and arranged to determine whetheranother vehicle is likely to impact the first vehicle in a mannerrequiring defensive action based at least in part on the at least one ofthe size, type, mass and orientation of the other vehicle and if so,affecting another system in the vehicle to initiate a warning ordefensive action. This system provides vehicle to vehicle communicationsbut does not provide a system which allows a vehicle to determine itslocation relative to fixed positions on a road or track. That systemalso suffers from the disadvantage of data storage problems due tounlimited data to be uploaded and stored including road edge detail forevery edge for every road and from each angle and direction. This isimpractical to implement and fails to address any changes in roadconfigurations i.e.: new structures like new round abouts or new roadislands or emergency works such as excavations and/or road maintenance.Also this known system does not distinguish navigation under bridges ormultiple store roads or tunnels.

U.S. Pat. No. 5,506,584 to Boles relates to a system for communicationbetween vehicles through a transmit and transponder relationship. Thepatent mentions that there may be as many as 90 vehicles within one halfmile of an interrogation device in a multi-lane environment, where manyof them may be at the same or nearly the same range. The Boles patentutilizes a transponder device, the coded responses which are randomizedin time and an interrogation device which processes the return signalsto provide vehicle identification speed, location and transponder statusinformation on vehicles to an operator or for storage in memory. Nomention is made of how a vehicle knows its location and therefore how itcan transmit that location to other vehicles.

U.S. Pat. No. 5,530,651 to Uemura, et al. discloses a combinationultrasonic and laser radar optical detection system which has thefeature that if the ability of the system to detect an obstacledecreases due to soiled lenses, rain, snow, etc., then the vehiclecontrol system automatically limits the speed, for example, that thevehicle can travel in the adverse weather conditions. The speed of thevehicle is also reduced when the visibility ahead is reduced due to ablind, curved corner.

U.S. Pat. No. 5,576,972 to Harrison provides a good background of howneural networks are used to identify various of objects. Although notdirectly related to intelligent transportation systems oraccident-avoidance systems, these techniques will be applied to theinvention described herein as discussed below.

U.S. Pat. No. 5,585,798 to Yoshioka, et al. uses a combination of a CCDcamera and a laser radar unit. The invention attempts to make a judgmentas to the danger of each of the many obstacles that are detected. Theload on the central processor is monitored by looking at differentobstacles with different frequencies depending on their danger to thepresent system. A similar arrangement is contemplated for the inventionas disclosed herein.

U.S. Pat. No. 5,572,428 to Ishida is concerned with using a radar systemplus a yawl rate sensor and a velocity sensor to determine whether avehicle will collide with another vehicle based on the area occupied byeach vehicle. Naturally, since radar cannot accurately determine thisarea it has to be assumed by the system.

U.S. Pat. No. 5,606,506 to Kyrtsos teaches a background to the GPSsatellite system. It discloses a method for improving the accuracy ofthe GPS system using an inertial guidance system. This is based on thefact that the GPS signals used by Kyrtsos do not contain a differentialcorrection and the selective access feature is on. Key paragraph fromthis application that is applicable to the instant invention follow.

There already exists a terrestrial position determination system,referred to generically as a global positioning system (GPS). A GPS is asatellite-based radio-navigation system that is intended to providehighly accurate three-dimensional position information to receivers ator near the surface of the Earth. This general capability is integratedin the present invention as part of a collision warning system.Triangulation, using at least three orbiting GPS satellites, allows theabsolute terrestrial position (longitude, latitude, and altitude withrespect to the Earth's center) of any Earth receiver to be computed viasimple geometric theory. The accuracy of the position estimate dependsin part on the number of orbiting GPS satellites that are sampled. Usingmore GPS satellites in the computation can increase the accuracy of theterrestrial position estimate.

Conventionally, four GPS satellites are sampled to determine eachterrestrial position estimate. Three of the satellites are used fortriangulation, and a fourth is added to correct for clock bias. If areceiver's clock were precisely synchronized with that of the GPSsatellites, then the fourth satellite would not be necessary.

In addition to the clock error, the atmospheric error and errors fromselective availability, other errors which affect GPS positioncomputations include receiver noise, signal reflections, shading, andsatellite path shifting (e.g., satellite wobble). These errors result incomputation of incorrect pseudoranges and incorrect satellite positions.Incorrect pseudoranges and incorrect satellite positions, in turn, leadto a reduction in the precision of the position estimates computed by avehicle positioning system.

U.S. Pat. No. 5,613,039 to Wang, et al. is a collision warning radarsystem utilizing a real time adaptive probabilistic neural network. Wangdiscloses that 60% of roadway collisions could be avoided if theoperator of the vehicle was provided warning at least one-half secondprior to a collision. The radar system used by Wang consists of twoseparate frequencies. The reflective radar signals are analyzed by aprobabilistic neural network that provides an output signal indicativeof the likelihood and threat of a collision with a particular object.The system further includes a Fourier transform circuit that convertsthe digitized reflective signal from a time series to a frequencyrepresentation. It is important to note that in this case, as in theothers above, true collision avoidance will not occur since, without aknowledge of the roadway, two vehicles can be approaching each other ona collision course, each following a curved lane on a highway and yetthe risk of collision is minimal due to the fact that each vehicleremains in its lane. Thus, true collision avoidance cannot be obtainedwithout an accurate knowledge of the road geometry.

U.S. Pat. No. 5,757,646 to Talbot, et al. illustrates the manner inwhich centimeter level accuracy on the fly in real time is obtained. Itis accomplished by double differencing the code and carrier measurementsfrom a pair of fixed and roving GPS receivers. Extremely accurate GPSreceivers depend on phase measurements of the radio carriers that theyreceive from various orbiting GPS satellites. Less accurate GPSreceivers simply develop the pseudoranges to each visible satellitebased on the time codes being sent. Within the granularity of a singletime code, the carrier phase can be measured and used to compute rangedistance as a multiple of the fundamental carrier wavelength. GPS signaltransmissions are on two synchronous, but separate carrier frequencies“L1” and “L2”, with wavelengths of nineteen and twenty-four centimeters,espectively. Thus within nineteen or twenty-four centimeters, the phaseof the GPS carrier signal will change 360.degree.

There are numerous prior art methods for resolving integer ambiguities.These include integer searches, multiple antennas, multiple GPSobservables, motion-based approaches, and external aiding. Searchtechniques often require significant computation time and are vulnerableto erroneous solutions or when only a few satellites are visible. Moreantennas can improve reliability considerably. If carried to an extreme,a phased array of antennas results whereby the integers are completelyunambiguous and searching is unnecessary.

But for economy the minimum number of antennas required to quickly andunambiguously resolve the integers, even in the presence of noise, ispreferred.

Work has been done to develop a target recognition system. Neuralnetworks pay a key role in that target recognition process. Therecognition of vehicles on a roadway is a considerably simpler process.Through range gating, most of the cluttering information can beeliminated. Road and Intersection Detection and Traversal, “IEEEConference on Intelligent Robots and Systems, Aug. 5-9, 1995,Pittsburgh, Pa., USA) describes an autonomous land vehicle using aneural network. The neural network is trained based on how a driverdrives the vehicle given the output from a video camera. The output ofthe neural network is the direction that the vehicle should head basedon the input information from the video camera and the training based onwhat a good driver would have done. Such a system can be used in thepresent invention to guide a vehicle to a safe stop in the event thatthe driver becomes incapacitated or some other emergency situationoccurs wherein the driver is unable to control the vehicle. The input tothe neural network in this case would be the map information rather thana video camera. Additionally, the laser radar imaging system could alsobe an input to the system. This neural network system could also takeover in the event that an accident becomes inevitable.

Rail disasters in recent years have highlighted that the current stateof the rail networks is no longer accepted worldwide. There seems to bea growing acceptance of the fact that the network and the service are inurgent need of major work to be done. Major improvements are needed inregards to safety, reliability, communications and the current culture.Train accidents are one of the most serious problems faced by oursociety, both in terms of personal deaths and injuries, and in financiallosses suffered as a result of accidents. Human suffering caused bydeath or injury from such accidents is immense. In addition, the costsof medical treatment, permanent injury to accident victims resulting inloss of life opportunities, and financial losses resulting from damageto trains and other valuable objects or structures involved in suchaccidents are staggering. Providing improved systems and methods tominimize such personal and financial losses is an urgent and veryimportant problem deserving the highest possible priority. Increasingpopulations and increased use of railway networks worldwide withresulting increased congestion and complications on our railway systemnetworks, makes development of improved control and warning systems forcollision avoidance even more important. While many advances have beenmade in vehicle safety, including, for example, the use of seatbelts,airbags and more rigid and safer automobile body structures, much roomfor improvement exists in railway systems, in general, and intrain-on-the-track warning and Control systems, in particular.

Positioning Self and Multiple Targets by GPS

For example, impressive advances have been made in various areas oftechnology that can be applied to the train collision avoidance andwarning system problem. One dynamic area of rapid technologicaldevelopment exists today in the form of GPS satellite location andtracking systems. As described above many patents have been issued forvarious applications of GPS for locating and tracking objects, and fornavigation purposes. Also, such GPS systems have been augmented withmethods that provide higher accuracy with real time, kinematicpositioning information for use in aircraft landing systems. Variousconfigurations of GPS-based tracking and communication systems andmethods are described in the following documents, each of which isincorporated in its entirety herein by reference: Logsdon, Tom, TheNavstar Global Positioning System, Van Nostrand Reinhold, New York(1992), ISBN 0-422-010404-0; Leick, Alfred, GPS Satellite Surveying,John Wiley & Sons, New York (1990), ISBN 0-471-81990-5; Hum, Jeff, GPS—AGuide to the Next Utility, Trimble Navigation, Ltd., Sunnyvale, Calif.(1989); Hum, Jeff, Differential GPS Explained, Trimble Navigation Ltd.,Sunnyvale, Calif. (1993); Singh, M. S. and Grewal, H. K., IEEEIntelligent Vehicle Symposium, September, (1995); Walter, T., et.al.,Flight Trials of the Wide-Area Augmentation System (WAAS), ION GPS-94,September, (1994); Walter, T. and Euge, P., Weighted RAIM for PrecisionApproach, ION GPS-95, September, (1995); and Remondi U.S. Pat. No.5,442,363; Okamoto U.S. Pat. No. 5,434,787; Dekel U.S. Pat. No.5,430,656; Sprague U.S. Pat. No. 5,422,816; Schuchman U.S. Pat. No.5,422,813; Penny U.S. Pat. No. 5,414,432; Smith U.S. Pat. No. 5,408,238;Gooch U.S. Pat. No. 5,396,540; Sennott U.S. Pat. No. 5,390,125; KassU.S. Pat. No. 5,389,934; FitzGerald U.S. Pat. No. 5,382,958; Brown U.S.Pat. No. 5,379,224; Class U.S. Pat. No. 5,361,212; Allison U.S. Pat. No.5,359,332: Bird U.S. Pat. No. 5,418,537; Izidon U.S. Pat. No. 5,325,302;Gildea U.S. Pat. No. 5,345,244; Brown U.S. Pat. No. 5,311,194; MuellerU.S. Pat. No. 5,323,322; Teare U.S. Pat. No. 5,243,652; Brown U.S. Pat.No. 5,225,842; Mansell U.S. Pat. No. 5,223,844; Geier U.S. Pat. No.5,202,829; Bertiger U.S. Pat. No. 5,187,805; Ferguson U.S. Pat. No.5,182,566; Hatch U.S. Pat. No. 5,177,489; Fraughton U.S. Pat. No.5,153,836; Allison U.S. Pat. No. 5,148,179; Joguet U.S. Pat. No.4,894,655.

Avoidance Determinations

A wide variety of mechanisms are well known for detecting targets andobstacles and for determining a wide variety of collision relevantparameters relative to the detected targets. The sensed and calculatedinformation from the detected targets is employed in a wide variety ofknown contexts to avoid collision. Such known systems include a widevariety of optical, electro-optical, radar, lidar, and magnetic sensorand video imaging devices, including Maekawa U.S. Pat. No. 5,039,217;Taylor U.S. Pat. No. 5,249,157; Kajiwara U.S. Pat. No. 5,177,462; DeFourU.S. Pat. No. 5,291,196; Lemelson U.S. Pat. No. 4,979,029; Lemelson U.S.Pat. No. 4,969,038; Kelley U.S. Pat. No. 4,926,171; O'Brien U.S. Pat.No. 5,341,344; Shaw U.S. Pat. No. 5,314,037; Asbury U.S. Pat. No.5,189,426; Asbury U.S. Pat. No. 5,181,038; Asbury U.S. Pat. No.5,302,956; Butsuen U.S. Pat. No. 5,332,057; Broxmeyer U.S. Pat. No.5,369,591; Shyu U.S. Pat. No. 5,091,726; Chi U.S. Pat. No. 5,165,497;Mayeau U.S. Pat. No. 5,161,107; Kurami U.S. Pat. No. 5,081,585;Schwarzinger, Michael, Vision-Based Car-Following: Detection, Tracking,and Identification 7/92, pgs. 24-29; Yu, Xuan, Road Tracking, LaneSegmentation and Obstacle Recognition by Mathematical Morphology, 7/92,pgs. 166-172; Ulmer, Berhold, VITA-An Autonomous Road Vehicle (ARV) forCollision Avoidance in Traffic, 7/92, pgs. 36-41; Ulmer, Berhold,Autonomous Automated Driving in Real Traffic, 12/94, pgs. 2118-2125;Sekine, Manabu, Design Method for An Automotive Laser Radar System andFuture Prospects for Laser Radar, 7/92, pgs. 120-125; Rock, Denny,Intelligent Road Transit: The Next Generation, Al Expert, 4/94, pgs.17-24; Teuber, Jan, Digital Image Processing, Prentice Hall, N.Y., 1989;Graefe, Volker, Vision for Intelligent Road Vehicles, 7/92, pgs.135-140; Enkelman, W., Realization of Driver's Warning Assistant forIntersections, 7/92, pgs. 72-77; Efenberger, Wolfgang, AutomaticRecognition of Vehicles Approaching From Behind, 7/92, pgs. 57-62;Rossle, S., Real-Time Vision-Based Intersection Detection for a Driver'sWarning Assistant, 7/92, pgs. 340-44 each of which is incorporatedherein by reference in its entirety. However, these systems fail toprovide such back-up scanning and multiple target detection and trackingas part of an integrated GPS collision avoidance and warning systemcapable of multiple target, logic, higher accurate, train-on-the-track,operational environment.

FIELD OF THE INVENTION

This invention relates to methods and apparatus used in railway systemsfor the detection of a collision candidate, such as a forward orrearward approaching train or other track-occupying vehicle, and moreparticularly to the automated invocation of collision avoidancemeasures.

The invention further relates generally to an apparatus and method ofprecisely determining the actual position and attitude of a host trainoperating on a select course or path (a railway track) and of multiplemoving or fixed targets (trains), which represent potential collisionhazards with a host train, and, then, generating and displaying warningsignals and avoidance response to avoid the collision and, in theabsence of effective timely action by the host operator (the traindriver), automatically controlling the host train to avoid thecollisions and damage there from. More particularly, the inventionrelates to the use of a Global Positioning System (“GPS”), as theprimary host train and target locating system with what availableaccuracy, on a second communication link from one of a plurality ofstations having a known fixed position on the surface of the track(track transponders) range signals, for positive track identificationand including correction signals for correcting errors in the GPSranging signals for assistance in making further measurements for stillfurther improving the accuracy of the GPS ranging signals, furthersupplemented by any of a plurality of conventional digital computersystems to detect, recognize, track and predict the collision impactpoint of all relevant potential targets (other trains using the track).The invention further relates to multiple antennae, GPS determined trainattitude for use in generating train-on-the-track, multiple targetrelative location, and collision avoidance warnings and responses. Moreparticularly, the invention further relates to an inter-train and trainfor transmitting GPS, position data, as well as, relevant target data toother trains and central or local control centres for information andcontrol action. More particularly, the present invention still furtherrelates to the use of neural networks and logic rule sets for generatingand developing optimal and prioritised warning and avoidance responses,and generating related optimally coordinated control signals for allrelevant host train control systems which are then automaticallyimplemented, subject to operator intervention and override, to avoidcollisions or to optimise prevention of injury or damage.

There are occasional collisions of trains that occur even though mostlocomotives are equipped with voice communication systems that shouldenable the engineers to detect collision candidates in time to initiatecollision avoidance measures. There have been efforts to provide methodsand apparatus that will detect and automatically avoid train collisions.The present invention present proposed solutions to the long-standingproblem of vehicular collisions, some of them catastrophic, includingcollisions between trains. In train networks, there are provided radiocommunications so that a driver may contact another driver for a varietyof operational reasons. In addition, transponders provide area codes fora particular location which enables train drivers to identity theirpositions. In the event of a danger or breakdown all drivers may bealerted by an all points broadcast via the central broadcast. In generalterms the known systems employ either a track system circuit forpositional control, an axle counter system for single lines or a loopsystem. There are therefore existing methods to warn drivers ofimpending danger or simply to allow communications between drivers towarn for instance of a sick passenger. However these methods are subjectto human error, are inefficient and are labor intensive.

SUMMARY OF INVENTION

One aspect of the invention is a computer controlled collision avoidanceand warning method which includes the steps of receiving continuouslyfrom a network of satellites on a first communication link at one of aplurality of trains GPS ranging signals for initially accuratelydetermining the one's position on a track on a surface of the earth;receiving continuously at the one train on a second communication linkfrom one of a plurality of stations having a known fixed position on thesurface of the track (track based transponders) for positive trackidentification and correcting propagation delay errors in the GPSranging signals and for still further improving the accuracy of the GPSranging signals and of determining the one's position on a track on asurface of the earth; determining continuously at the one train from theGPS, the one's kinematic tracking position on the surface of the trackaugmented with neural networks to provide higher accuracy . . . ,communicating the one's status information including the kinematictracking position to each other one of the plurality of trains and tothe plurality of train control centres, and receiving at the one traineach of the others' of the plurality of train status informationincluding the others' kinematic tracking position; determining in alogic associative memory (LAM) the one's response relative to eachcollision hazard; generating control signals for actuating an overridecontrol mechanism, that interface with train controls, to stop thetrain/s short of a collision; intelligibly indicating a warning of acollision hazard; and, co-ordinately actuating the real-time logging oftrain characteristics in real time sufficiently in due time to avoideach collision hazard;

The present invention provides moving train collision avoidance, warningand control systems and methods using GPS satellite location systemsaugmented with neural networks to provide higher location accuracy, andto derive train attitude and position coordinates and one's kinematictracking information. Ground based controller computers are used tocommunicate with trains for the purpose of receiving location and trainstatus information and broadcasting control information to respectivetrains, such GPS location and computing systems being integrated withtrack transponders scanning and on-board Train Navigation Unit (TNU) toprovide accurate train location information together with informationconcerning impending collision situations for each train. The presentinvention and method disclosed herein will measure beneficially high inSafety and Environmental areas and will make the train controllers inmore control and the train operators, proactive rather reactive.

A further enhancement of the Train Navigation and Control System (TNCS)and method disclosed herein makes use of an essential tool for the traincontroller to stop the one train, or any other train, remotely, thatwill be introduced for the first time ever, to enable the traincontroller to prevent a disaster/s from happening, in such cases as:

stopping a break away trains, speeding trains towards a derailed trainor other disaster areas with no means to warn the train crew of a wrongrunning direction train, incapacitated driver or in fog, smoke or blindspots such as bends. This feature can be accommodated by theintroduction of Central Control Unit (CCU).

Real-time Logging of Train Characteristics

Yet, a further enhancement of the Train Navigation and Control System(TNCS) and method disclosed herein makes use of a real-time logging oftrain characteristics system to record the last several minutes ofdriving action for future analysis. Such recordings permitreconstruction of events leading up to collision permitting moreaccurate determination of causes including fault.

In a broad form of the system aspect the present invention comprises;

a computer controlled vehicle collision avoidance and warning system;the system comprising:

a central controller;

at least one satellite providing a first communication link between theat least one satellite and at least one Global Positioning System (GPS)to determine a position of a first vehicle;

a second communications link allowing communications between at leastone fixed station and a first said vehicle;

wherein said second communications link provides continualcommunications between said at least one fixed transponder station andat least one of a potentially unlimited number of other vehicles;wherein, said first communications link provides a location of any onesaid vehicles via GPS and wherein the communications between TNUs oneach vehicle provides a location of one vehicle relative to at least oneother vehicle.

In its broadest form, the present invention comprises:

a computer controlled vehicle collision avoidance and warning system;the system comprising:

at least one satellite in communication with at least one GlobalPositioning System (GPS device) providing a first communication linkbetween the at least one satellite to determine a location of at least afirst vehicle;

a second communications link allowing communications between at leastone fixed station and at least a first said vehicle;

wherein said second communications link provides continualcommunications between said at least one fixed station and at least oneof a potentially unlimited number of other vehicles; wherein, said firstcommunications link provides a location of any one said vehicles andsaid second communications link provides a location of one vehiclerelative to at least one other vehicle via processing means in each saidat least one vehicle.

Preferably, each fixed stations are located at a known position on avehicle path and at a predetermined distance from each other whereineach said fixed station includes a transponder which emits a rangesignal to the processing means in each vehicle for path identification.According to a preferred embodiment, each said vehicle is a traintraveling on a track network and the processing means comprises a trainnavigation unit (TNU). The system further comprises in association withsaid train navigation unit a main control unit; wherein the trainnavigation unit communicates with the main control unit to enable acomparison between train location data received via the firstcommunication link and train location data received from the secondcommunications link. The system preferably comprises a centralcontroller for remote monitoring of the system; wherein at least one ofthe satellites communicates with a train based GPS or a GPS associatedwith said central controller. Each fixed transponder station emitscorrection signals for correcting errors in GPS ranging signals from thefirst communications link wherein the correction signals allow furthercorrection measurements for improving the accuracy of the GPS rangingsignals. Track identification is computer processed in conjunction withthe controller to continuously determine a kinematic tracking of a trainfor position identification; wherein a tracked position of one train iscommunicated to or received by at least one other train in real time toallow each train to determine a distance of separation from at least oneother train. Preferably, there is a network of satellites which transmitcontinually to a GPS for allowing a determination of a train on a railtrack.

Preferably the range signals from each transponder allow determinationof a first train position relative to another train for determination ofa collision hazard.

In the event of a collision hazard a response control signal isgenerated for actuating an override control mechanism, whichcommunicates with train controls, to stop the train/s short of acollision. Processing of the location information of each said trainsmay be provided by a neural network which identifies and evaluates eachpotential collision hazard of one train relative to another train. Trainnavigation units (TNU's), provide real-time logging of traincharacteristics and allow determination of train location, length,velocity, speed relative to at least one other train. Preferably, thesystem further comprises alert means for alerting an operator of onetrain at one location to the presence of at least one other train atanother location.

The potential energy of a train in the network may be determined byreference to the known formula:

$\begin{matrix}{{P.E.} = {{({xEOB}) + {{Fb}\left( {{xEOB} - x} \right)}} = {{\frac{1}{2}m\;{v^{2}(x)}} + {P.E.(x)}}}} \\{where} \\{{Fb}\mspace{14mu}{is}\mspace{14mu} a\mspace{14mu}{braking}\mspace{14mu}{force}\mspace{14mu}{assumed}\mspace{14mu}{constant}\mspace{14mu}{at}\mspace{14mu}{full}\mspace{14mu}{service}\mspace{14mu}{application}} \\{M\mspace{14mu}{is}\mspace{14mu}{total}\mspace{14mu}{train}\mspace{14mu}{mass}} \\{V\mspace{14mu}{is}\mspace{14mu}{velocity}\mspace{14mu}{at}\mspace{14mu}{start}\mspace{14mu}{of}\mspace{14mu}{braking}} \\{{{P.E.\mspace{14mu}{is}}\mspace{14mu}{the}\mspace{14mu}{potential}\mspace{14mu}{energy}\mspace{14mu}{of}\mspace{14mu}{the}\mspace{14mu}{train}} = {\sum\limits_{n}{w_{n}h_{n}}}} \\{n\mspace{14mu}{is}\mspace{14mu}{the}\mspace{14mu}{number}\mspace{14mu}{of}\mspace{14mu}{cars}\mspace{14mu}{and}\mspace{14mu}{locomotives}}\end{matrix}$

The calculated potential energy determines quantum of braking effort toavoid a collision.

The system also includes a train GPS radio assembly including a GPSinterface sub system and a train navigation unit communicationsubsystem; wherein both said subsystems are in communication with atransceiver.

Preferably the system includes an override control including;

a signal input,

a detection signal analysis means;

a data source

a logic associative memory in communication with a control signalgenerator, wherein said control signal generator is capable of emittinga signal responsive to input data to override train controls to effectbraking in the event of a collision risk. The central controller iscapable of monitoring train locations over a range of approximately 600kms.

In another broad form the present invention comprises:

a computer controlled train collision avoidance and warning system; thesystem comprising:

at least one satellite in communication with at least one GlobalPositioning System (GPS device) providing a first-communication linkbetween the at least-one satellite to determine a location of at least afirst train;

a second communications link allowing communications between at leastone fixed transponder station and at least a first said train;

wherein said second communications link provides continualcommunications between said at least one fixed transponder station andat least one of a potentially unlimited number of other trains; wherein,said first communications link provides a location of any one saidvehicles and said second communications link provides a location of onetrain relative to at least one other train via processing means in eachsaid at least one train.

In another broad form the present invention comprises:

a computer controlled train collision avoidance and warning system; thesystem comprising:

at least one satellite in communication with at least one GlobalPositioning System (GPS device) providing a first communication linkbetween the at least one satellite to determine a location of at least afirst train;

a second communications link allowing communications between at leastone fixed station and at least a first said train;

wherein said second communications link provides continualcommunications between said at least one fixed transponder station andat least one of a potentially unlimited number of other trains; wherein,said first communications link provides a location of any one saidvehicles and said second communications link provides a location of onetrain relative to at least one other train via processing means in eachsaid at least one train;

wherein said second communications link provides continualcommunications between said at least one fixed transponder station andat least one of a potentially unlimited number of other trains; wherein,said first communications link provides a location of any one saidtrains and said second communications link allows determination of alocation of one train relative to at least one other train; wherein thesystem further comprises;

a signal input,

a detection signal analysis means;

a data source

a logic associative memory in communication with a control signalgenerator, wherein said control signal generator is capable of emittinga signal responsive to input data to override train controls to effectbraking in the event of a collision risk.

Preferably a central controller is capable of communication with atleast one of the satellites to monitor train location and to issue awarning in the event of a collision risk.

In another broad form according to a method aspect the present inventioncomprises:

a method of preventing vehicle collisions comprising;

a computer controlled vehicle collision avoidance and warning system;the system comprising:

at least one satellite in communication with at least one GlobalPositioning System (GPS device) providing a first communication linkbetween the at least one satellite to determine a location of at least afirst vehicle;

a second communications link allowing communications between at leastone fixed station and at least a first said vehicle;

wherein said second communications link provides continualcommunications between said at least one fixed station and at least oneof a potentially unlimited number of other vehicles; wherein, said firstcommunications link provides a location of any one said vehicles andsaid second communications link provides a location of one vehiclerelative to at least one other vehicle via processing means in each saidat least one vehicle;

the method comprising the steps of:

-   -   a) using the first communication link to provide a location of a        first vehicle;    -   b) activating a GPS radio system including a GPS interface and a        communication subsystem;    -   c) placing track identification means at predetermined track        locations to provide signals of track identification to        vehicles;    -   d) receiving input data relating to train operation and        environment parameters    -   e) analyzing said data via a logic associative memory; to        determine a collision risk between at least two vehicles;    -   f) activating an override signal responsive to a collision risk        in the event that one train is on a collision course with        another train.

The method comprises the further step of allowing each vehicle toreceive a signal indicative of a predetermined location on a vehiclepath.

The method includes the preliminary step of locating at each fixedstation, transponders on a vehicle path at a known position and at apredetermined distance from each other;

wherein, each transponder emits a range signal for path identification;wherein the path is a road or a railway track.

Each fixed transponder station emits correction signals for correctingerrors in GPS ranging signals from the first communications link;wherein the correction signals allow further correction measurements forimproving the accuracy of the GPS ranging signals The method comprisesthe further step of providing a central controller for monitoringvehicle locations and capable of transmitting an override signal tovehicles to actuate a collision avoidance feature. According to oneembodiment, the method comprises the further step of processingpositions of each vehicle received and/or transmitted to each vehiclevia a neural network; wherein the neural network identifies andevaluates each potential collision hazard of one train relative toanother train.

A network of satellites transmit continually to a GPS for allowing adetermination of a train on a rail track. Transponder range signals toallow determination via the neural network in a logic associative memory(LAM) of a first train position relative to another train fordetermination of a collision hazard. In the event of a collision hazarda response control signal is generated for actuating an override controlmechanism, which communicates with train controls, to stop the train/sshort of a collision.

In another broad form of a method aspect, the present inventioncomprises:

a method for operating a collision warning and avoidance systemcomprising the steps of:

a) providing a network of satellites capable of continuouscommunications via a first communications link with one or more of aplurality of trains

b) ranging signals for initially accurately determining a train positionon a rail track,

c) receiving continuously a signal at each said train via a secondcommunication link from one of a plurality of transponder stationshaving a known fixed position on the surface of the track;

d) determining in a logic associative memory (LAM) a response whichgenerates control signals, that actuate an override control mechanism,that influences train controls to stop the train/s short of a collisionin the event of a detected collision risk.

The method preferably, comprises the further step of real-time loggingof train characteristics to record the last several minutes of drivingaction to thereby enable reconstruction of events leading up to acollision.

A train navigation unit (TNU) provides remote train control override fora train controller to stop at least one train in the event of acollision risk.

In another broad form of a method aspect, the present inventioncomprises:

a method of preventing train collisions comprising;

a computer controlled collision avoidance and warning system; the systemcomprising:

at least one satellite in communication with at least one GlobalPositioning System (GPS device) providing a first communication, linkbetween the at least one satellite to determine a location of at least afirst train;

a second communications link allowing communications between at leastone fixed transponder station and at least a first said train;

wherein said second communications link provides continualcommunications between said at least one fixed transponder station andat least one of a potentially unlimited number of other trains; wherein,said first communications link provides a location of any one saidtrains and said second communications link provides a location of onetrain relative to at least one other train via processing means in eachsaid at least one vehicle; the method comprising the steps of:

-   -   a) activating a GPS radio system including a GPS interface and a        communication subsystem;    -   b) using the first communication link to provide a location of        each one of a plurality of trains;    -   c) receiving at a main control unit input data relating to train        operation and environment parameters    -   d) analyzing said data via a logic associative memory; to        determine a collision risk between at least two trains;    -   e) activating an override signal responsive to a collision risk        in the event that one train is on a collision course with        another train.

In another broad form according to a method aspect the present inventioncomprises:

a method of preventing vehicle collisions using a system comprising;

a computer controlled vehicle collision avoidance and warning system;the system comprising:

at least one satellite providing a first communication link between theat least one satellite and at least one Global Positioning System (GPSdevice) to determine a location of a first vehicle;

a second communications link allowing communications between at leastone fixed transponder station and at least a first said vehicle;

a central controller;

wherein said second communications link provides continualcommunications between said at least one fixed transponder station andat least one of a potentially unlimited number of other vehicles;wherein, said first communications link provides a location of any onesaid vehicles and the communications between train navigations units(TNUs), provides a location of one vehicle relative to at least oneother vehicle the method comprising the steps of:

-   -   a) using the first communication link to provide a location of a        first vehicle;    -   b) activating a GPS radio system including a GPS interface and a        communication subsystem;    -   c) receiving input data relating to train operation and        environment parameters;    -   d) placing track identification means at predetermined track        locations to provide signals of track identification to        vehicles;    -   e) analyzing said data via a logic associative memory to        determine a collision risk between at least two vehicles;    -   f) activating an override signal responsive to a collision risk        in the event that one train is on a collision course with        another train.

DESCRIPTION OF THE DRAWINGS

The present invention will now be described in more detail withaccording to a preferred but non limiting embodiment and with referenceto the accompanying illustrations wherein;

FIG. 1 shows a schematic layout of a train navigation and control system(TNCS) according to one embodiment;

FIG. 2 shows a first communication link being a GPS receiver and asecond communication link being a GPS transceiver each operating onseparate predetermined frequencies.

FIG. 3 shows a schematic of typical trains in a network the receivinginformation from one another on parameters associated with the operationof the other train.

FIG. 4 shows a plan view of a train and track assembly including a GPSsubsystem interface unit fitted to the train.

FIG. 5 shows a schematic layout of a typical procedure for processingand analyzing inputs and transmitting data derived from those inputs.

FIG. 6 shows a plan view of a typical track and trains arrangementincluding a Transponder Identification Subsystem (TIS) capable ofinteraction with a train to sense track mounted transponders, whichprovide the exact location of the train relative to the transponders.

FIG. 7 shows a plan view of an arrangement of fixed point transponders33 for determining, using a scanner supported on a train, particulartrack identification.

FIG. 8 shows a schematic layout of a GPS interface subsystem and TNUcommunication subsystem and software module.

FIG. 9 shows one train having 2 TNUs: GPS transceivers preferably frontand rear for the purpose of determining the length of the train.

FIG. 10 shows a known formula for determining potential energy of atrain from parameters such as relative velocity between two trains,track topography on which the one train is traveling, to determiningbraking effort.

FIG. 11 shows a graphical representation of an algorithm for processingan input signal responsive to train parameters such as minimum brakingdistance of a train according to predetermined train parameters.

FIG. 12 shows a schematic layout of an interface between input signals alogic associative memory and train controls which provides controlsignals, that actuate an override control mechanism, that interface withtrain controls, to stop the train/s short of a collision.

FIG. 13 shows a schematic layout of a process for determining a hazardvector and collision vector and analyzing both vectors for generatingoutput signals for preventing a collision.

FIG. 14 shows a main control unit (MCU) is featuring neural networks toprocess and analyze received data and information for analysis tocalculate parameters such as speed, direction and location of a train.

FIG. 15 shows schematic inputs and outputs of a known neural network.

FIG. 16 shows graphical relationships for connecting the outputs of afirst node layer to a third node layer through a second connectionlayer; and combining the outputs of the second node layer to providereceiver position data

FIG. 17 shows a graphical arrangement providing a comparison betweenoutput signals to a desired signal to produce an error signal; andapplying the error signal to a training algorithm to determine a weight.

FIG. 18 shows a schematic layout of a train navigation unit andrelationships with operation parameters according to one embodiment ofthe invention.

DETAILED DESCRIPTION OF INVENTION

The present invention in one broad form provides a computer controlledcollision avoidance and warning system in which signals are received byat least one vehicle on a first communication link from a GPS satellitelink for determining the position of that vehicle. The invention furtherprovides a second communications link in which at least one of aplurality of vehicles receive continuously a signal concerning theposition of at least one other vehicle so that each vehicle known theposition of another vehicle so that evasive action may be taken in theevent of a collision. The first communications link is a GPS receiverand the second communications link is a GPS transceiver each operatingon separate predetermined frequencies. (see FIG. 2).

Although the present invention will be described with reference to itsapplication to train collision warning it will be appreciated by personsskilled in the art that the invention has applications for vehiclecollision management in a variety of areas other than traininfrastructure networks.

FIG. 1 shows a schematic layout of a train navigation and control system(TNCS) according to one embodiment. The TNCS includes a GlobalPositioning System 1 comprising (at least one) satellite 2 whichcommunicates with a transceiver 3 located in at least one train 4. Eachtrain has a Main Control Unit 5, a train communication subsystem 6 andGPS interface subsystem 7. GPS interface subsystem 7 communicates withGPS satellite 2 for the purpose of establishing positional data fortrain 4. This constitutes a first communication system. Working inconjunction with the first communication system is a secondcommunication system which eventually allows one train to communicatevia a communications link 8 with at least one other train via a CentralControl Unit (CCU) 9. The second communications link provides trainlocation and operational parameter data for analysis by the centralcontrol unit so this information may be available to another train forthe purpose of collision avoidance. This is effected by use of a trainnavigation unit and main control unit which are in mutual communication.Referring to the Train navigation unit of FIG. 1 there is providedaccording to one embodiment, a host computer system associated with theCentral Control Unit (CCU), having at least one application programlocated at the train controller facility 9, that controls the area inwhich a local host user, on-board TNU interface is located.

A host transceiver system, includes means for gathering output from theCCU 9 and means for providing input into the host computer system. Atrain controller interface is coupled to the host computer system at theCCU 9. A redundant user interface configured to be used in at least oneremote location, the TNU on-board. The controller interface includesmeans for producing output gathered by the host transceiver system fromthe host computer system. The controller interface also includes meansfor gathering user input for insertion by the host transceiver systeminto the host computer system.

FIG. 2 shows a schematic layout of the main hardware for the first andsecond communications links. The first communications link comprises apotentially unlimited number of satellites but in the case of theembodiment of FIG. 2 there are four satellites 10, 11, 12 and 13.Satellite 10 is capable of communication via a first communication link14 to a GPS receiver on board train 15 or to a central control center16. A radio link 17 allows communication via communications tower 18between train controller 16 and (at least one) train 15. Traincontroller 16 is in communication with each train via control link 19.GPS transceivers associated with each train each operate on separatepredetermined frequencies. A communications link capable ofcommunicating to and from the at least one remote location is configuredto send output gathered by a host transceiver system to the controllerinterface. The communications link is also configured to send inputgathered by the controller interface to the host transceiver system.

FIG. 3 shows a schematic of typical trains 20 and 21 in a networkreceiving information from one another on parameters associated with theoperation of the other train. Primary communications is via at least onesatellite 22. Thus each train will know at any time the location of atleast one other train and particularly a train on a collision coursewith the train.

FIG. 4 shows a plan view of a train 23 having a leading end 24 and atrailing end 25. Train 23 travels on track 26 and includes a first GPSsubsystem 27 and a second GPS subsystem unit 28.

FIG. 5 shows a schematic layout/data flow chart of a typical procedurefor processing and analyzing inputs and transmitting data derived fromthose inputs. The analysis includes analyzing train's attitude, and thecompensating attitude response once GPS data has been acquired.According to one embodiment, once GPS data has been acquired, thefollowing information is obtained: speed, direction, track ID, train ID.Acquired data is then formatted and transmitted for processing. Theanalysis further comprises: analyzing inputs of characteristics of eachand every individual train.

FIG. 6 shows a plan view of a typical track 30 with trains traveling inopposition poll arrangement including a Transponder IdentificationSubsystem (TIS) capable of interaction with a train to sense trackmounted transponders 31. The TIS provides an interface for the train 29to sense fixed position transponders 31 mounted on track 30. The TISidentifies precisely the transponder which the train is approaching orpassing. So that the precise location of the transponder may bedetermined. The attitude of train 29 (kinematic position) may bedetermined continuously relative to a fixed point on surface of track 30by transponders 31. This may be achieved by use of a scanner (not shown)at train extremities and comparing GPS signals simultaneously receivedat a scanner antennae. The TIS maintains an up to date data base of alltransponders, their location and the Track ID on which they are located.

FIG. 7 shows a plan view of an arrangement of fixed point transponders33 for determining, using a scanner supported on a train, for particulartrack identification.

FIG. 7 shows different track identities. For instance transponders 36-39represent tracks A (32), B (33), D (34) and C (35) respectively.

FIG. 8 shows a schematic layout of a GPS interface subsystem and TNUcommunication subsystem and software module. GPS Interaface subsystem(GIS) 40 accepts inputs from GPS satellites (see FIG. 2). GIS 40includes a receiver/transmitter 41 and 42 respectively and a softwaremodule. The software module manages communications between the GPS unitand all other system components thereby providing the necessary datacaching and timing. Preferably the software module reads satellite dataevery 30 seconds. GIS 40 calculates the position of the train, its speedbased on the information received and the time of day. Traincommunication subsystem TCS 43 broadcasts train information every 1minute and includes train identification, current position, speed,direction and track identification. This information is provided by eachtrain and is available to each other train in the network via a centralcontrol unit. Train communication subsystem works as a master TCS forone train with all other on board components of the system acting asback up for the master TCS. This is achieved through the election andelimination mode as shown in FIG. 9.

FIG. 9 shows a train 44 of indefinite length L having a transceiver 45at one end and a transceiver 46 at an opposite end. These transceiversallow determination of the length of train 44.

TCS units on one train will elect one unit as a master TCS for thattrain so that all remaining units of the on board system will be back upfor the TCS. The TCS comprises Communications include communicating thestatus information of one selected train and the receiving step includesreceiving status information on another train. Each train is engaged inassociation with the central controller of receipt and transmission ofinformation which is processed at the central controller for collisionrisk analysis. Train 44 of FIG. 9 includes train navigation unit (TNU)election and elimination mode (EEM) for determination of a train lengthcomprise The TCS (see FIG. 8) works as a master TCS for one train andall other on-board units will work as backup for the master TCS. This isachieved through the election and elimination mode (EEM).

The TCS units on the same train have to elect one unit to work as masterTCS for that train and all other units will work as backup for the materTCS.

The EEM is enabled automatically when the TNU units are turned on orwhen the master TCS unit no longer broadcasts the train information. TheTCS accurately calculates the exact length of the train even afteramalgamating or dividing the one train. This reduces labor and helps tostreamline the operation of the TNCS.

The TCS comprises a time lock feature in the one train stationarystatus, for example laps (X) minutes, to cancel this mode

FIG. 10 shows a formula for determining potential energy (PE) of a trainfrom parameters such as relative velocity between two trains, tracktopography on which the one train is traveling, i.e. Steep grade,downhill or flats. This enables calculation of train parameters so thatcollision risk can be determined by any train at any time based on awide variety of train parameters such as but not limited to, Brakingforce (assumed constant at full service application), train mass,velocity at the start of braking, the number of cars and locomotiveswhich make up the train. The calculated potential energy may multiply bya safety factor designed on a brake condition (such as overheated orfrequently used brakes, wear of brake shoes).

FIG. 11 shows a graphical representation of an algorithm for processingan input signal responsive to train parameters such as velocity andminimum braking distance of a train according to predetermined trainparameters.

FIG. 12 shows a schematic layout of an interface 50 between inputsignals 51, a logic associative memory 52 and train controls whichprovides control signals via a control signal generator 53, that actuatean override control mechanism, that interface with train controls, tostop the train/s short of a collision. According to one embodiment,override control signal generator activates a micro switch (not shown)that activates known dead man mechanism 54 or like train feature todisable a train throttle or the like in one train. The override willstop the train by reducing the brake pipe pressure to maximize the brakecylinder pressure.

FIG. 13 shows a schematic layout of a process for determining a hazardvector and collision vector and analyzing both vectors for generatingoutput signals for preventing a collision. The analysis involvescalculating a collision vector for each collision hazard and determininga collision avoidance procedure. Warning indication involves warning thedriver of one train of a TNU response and actuating an override controlmechanism (see arrangement of FIG. 12), should a collision remainimminent at the end of a warning period. The warning may be implementedby visually indicating to the driver of one train on an LC display onthe relevant train. A warning may also be implemented by actuating acollision warning light and/or sound system.

FIG. 14 shows a main control unit (MCU) is featuring neural networks toprocess and analyze received data and information for analysis tocalculate parameters such as speed, direction and location of a train.

FIG. 15 shows a schematic of inputs and outputs of a neural network usedas an intelligence to “learn” data for use in the system

FIG. 16 shows graphical relationships for connecting the outputs of afirst node layer to a third node layer through a second connectionlayer; and combining the outputs of the second node layer to providereceiver position data The neural network improves the accuracy of datafrom the GPS signals for more accurate determination of train position.The method comprises receiving input signals via a GPS receiver from atleast one of GPS satellite. The input signals comprise satellite-relatednavigation information. The input signals are connected to the secondnode layer through the first node layer and the first connection layer.The outputs of the second node layer to the third node layer areconnected to the second connection layer. The outputs are connected tothe second node layer to provide receiver position data as shown in FIG.16. Weighting the second connection layer comprises: comparing theoutput signals to a desired signal to produce a position error signal;and applying the error signal to a training algorithm to determine aweight as shown in FIG. 17.

FIG. 17 shows a graphical arrangement providing a comparison betweenoutput signals to a desired signal to produce an error signal; andapplying the error signal to a training algorithm to determine a weight.

FIG. 18 shows a schematic layout of a train navigation unit andrelationships with operation parameters according to one embodiment ofthe invention. As can be seen from the schematic of FIG. 18, at theheart of the invention is the train navigation unit (TNU) which islinked to all facets of the collision avoidance and warning system. Awide number of train and train environment parameters are catered for toenable calculation of collision risk via primary and secondarycommunications links. The environmental parameters include topographyand global positioning location and track identification.

Train parameters include train identification, braking data, velocity,acceleration, speed, weight, length of train. The train communicationsubsystem comprises a time lock feature in the one train stationarystatus, for example laps (X) minutes, to cancel this mode automatically.TCS accurately calculates the exact length of the train afteramalgamating or dividing the one train. This minimises human interactionand helps to streamline the operation of the TNCS.

Variable TNU inputs due to changing of the characteristics of anindividual train or its surrounding moving environment will result invariable TNUs' calculations which will allow the TNU to deactivate whenthe potential hazard disappears or is eliminated by changing the track(X-over) or the one train speed is brought under control by the driveror by clearing the Signal ahead. This feature will allow the TNU not tobring the one train to a complete stand before releasing the brakes andpick-up speed again, which will achieve smooth riding and a power savingTrain Managing System as well as maintaining the timetables and enforcethe safe working procedures by controlling the train speed to take placein X-overs and on peak hour's movements (when the Trains are closelyfollowing each other).

The foregoing description of a preferred embodiment and best mode of theinvention known to applicant at the time of filing the application hasbeen presented for the purposes of illustration and description. It isnot intended to be exhaustive or to limit the invention to the preciseform disclosed, and obviously many modifications and variations arepossible in the light of the above teaching. The embodiment was chosenand described in order to best explain the principles of the inventionand its practical application to thereby enable others skilled in theart to best utilize the invention in various embodiments and withvarious modifications as are suited to the particular use contemplated.It is intended that the scope of the invention be defined by the claimsappended hereto.

1. A computer controlled train collision avoidance and warning system;the system comprising: at least one satellite in communication with atleast one Global Positioning System device providing a firstcommunication link between the at least one satellite to determine alocation of at least a first train; a second communications linkallowing communications between at least one fixed station and at leasta first said train; wherein said second communications link providescontinual communications between said at least one fixed station and atleast one of a potentially unlimited number of other trains; wherein,said first communications link provides a location of any one saidtrains and said second communications link provides a location of onetrain relative to at least one other train via processing means in eachsaid at least one train; wherein, each said fixed stations are locatedat a known position on a rail track and at a predetermined distance fromeach other; wherein, each said fixed station includes a transponderwhich emits a range signal to said processing means in each train fortrack identification; and wherein each fixed transponder station furtheremits correction signals for correcting errors in Global PositioningSystem signals from said first communications link to enabledetermination of exact track separation of trains on a track networkallowing for respective train lengths and track curvature.
 2. A systemaccording to claim 1 wherein said correction signals allow furthercorrection measurements for improving the accuracy of the GlobalPositioning System ranging signals.
 3. A system according to claim 2wherein the processing means comprises a train navigation unit.
 4. Asystem according to claim 3 further comprising in association with saidtrain navigation unit a main control unit.
 5. A system according toclaim 4 wherein the train navigation unit communicates with said maincontrol unit to enable a comparison between train location data receivedvia said first communication link and train location data received fromsaid second communications link.
 6. A system according to claim 5further comprising a central controller for remote monitoring of saidsystem.
 7. A system according to claim 6 wherein, each said at least onesatellite communicates with a train based Global Positioning System or aGlobal Positioning System associated with said central controller.
 8. Asystem according to claim 7 wherein path identification is computerprocessed in conjunction with said controller to continuously determinea kinematic tracking of a train for position identification.
 9. A systemaccording to claim 8 wherein a tracked position of one train iscommunicated to or received by at least one other train in real time toallow each said trains to determine a distance of separation from atleast one other train.
 10. A system according to claim 9 wherein thereis a network of satellites which transmit continually to a GlobalPositioning System for allowing a determination of a position of a trainon a rail track.
 11. A system according to claim 10 wherein rangesignals from each said transponder allow determination of a first trainposition relative to another train for determination of a collisionhazard.
 12. A system according to claim 11 wherein, in the event of acollision hazard a response control signal is generated for actuating anoverride control mechanism, which communicates with train controls, tostop the trains short of a collision.
 13. A system according to claim 12wherein the processing of said location information of each said trainsis provided by a neural network which identifies and evaluates eachpotential collision hazard of one train relative to another train.
 14. Asystem according to claim 13 wherein said train navigation units providereal-time logging of train characteristics.
 15. A system according toclaim 14, further comprising means for determining train location,length, velocity, speed relative to at least one other train.
 16. Asystem according to claim 15, further comprising alert means foralerting an operator of one train at one location to the presence of atleast one other train at another location.
 17. A system according toclaim 16 wherein the potential energy of a train in said network isdetermined by reference to the formula: $\begin{matrix}{{P.E.} = {{({xEOB}) + {{Fb}\left( {{xEOB} - x} \right)}} = {{\frac{1}{2}m\;{v^{2}(x)}} + {P.E.(x)}}}} \\{where} \\{{{Fb}\mspace{14mu}{is}\mspace{14mu} a\mspace{14mu}{braking}\mspace{14mu}{force}\mspace{14mu}{assumed}\mspace{14mu}{constant}\mspace{14mu}{at}\mspace{14mu}{full}\mspace{14mu}{service}\mspace{14mu}{application}},} \\{{M\mspace{14mu}{is}\mspace{14mu}{total}\mspace{14mu}{train}\mspace{14mu}{mass}},} \\{{V\mspace{14mu}{is}\mspace{14mu}{velocity}\mspace{14mu}{at}\mspace{14mu}{start}\mspace{14mu}{of}\mspace{14mu}{braking}},} \\{{{{P.E.\mspace{14mu}{is}}\mspace{14mu}{the}\mspace{14mu}{potential}\mspace{14mu}{energy}\mspace{14mu}{of}\mspace{14mu}{the}\mspace{14mu}{train}} = {\sum\limits_{n}{w_{n}h_{n}}}},{and}} \\{n\mspace{14mu}{is}\mspace{14mu}{the}\mspace{14mu}{number}\mspace{14mu}{of}\mspace{14mu}{cars}\mspace{14mu}{and}\mspace{14mu}{{locomotives}.}}\end{matrix}$
 18. A system according to claim 17 wherein the calculatedpotential energy determines quantum of braking effort to avoid acollision.
 19. A system according to claim 1 further comprising a trainGlobal Positioning System radio assembly including a Global PositioningSystem interface sub system and a train navigation unit subsystem;wherein both said subsystems are in communication with a transceiver.20. A system according to claim 19 further comprising: an overridecontrol including; a signal input, a detection signal analysis means; adata source; and a logic associative memory in communication with acontrol signal generator, wherein said control signal generator iscapable of emitting a signal responsive to input data to override traincontrols to effect braking in the event of a collision risk.
 21. Asystem according to claim 20 wherein a central controller is capable ofmonitoring train locations over a range of approximately 600 kms.
 22. Acomputer controlled train collision avoidance and warning system; thesystem comprising: at least one satellite in communication with at leastone Global Positioning System device providing a first communicationlink between the at least one satellite to determine a location of atleast a first train; a second communications link allowingcommunications between at least one fixed station and at least a firstsaid train; wherein said second communications link provides continualcommunications between said at least one fixed transponder station andat least one of a potentially unlimited number of other trains; wherein,said first communications link provides a location of any one saidtrains and said second communications link provides a location of onetrain relative to at least one other train via processing means in eachsaid at least one train; wherein said second communications linkprovides continual communications between said at least one fixedtransponder station and at least one of a potentially unlimited numberof other trains; wherein, said first communications link provides alocation of any one said trains and said second communications linkallows determination of a location of one train relative to at least oneother train; and wherein each fixed transponder station further emitscorrection signals for correcting errors in Global Positioning Systemsignals from said first communications link to enable determination ofexact track separation of trains on a track network, allowing forrespective train lengths and track curvature, wherein the system furthercomprises; a signal input, a detection signal analysis means; a datasource; and a logic associative memory in communication with a controlsignal generator, wherein said control signal generator is capable ofemitting a signal responsive to input data to override train controls toeffect braking in the event of a collision risk.
 23. A system accordingto claim 22 further comprising a central controller capable ofcommunication with at least one said satellites to monitor trainlocation and to issue a warning in the event of a collision risk.
 24. Asystem according to claim 23 wherein the central controller is capableof monitoring train locations over a range of approximately 600 kms. 25.A method of preventing train collisions comprising; a computercontrolled train collision avoidance and warning system; the systemcomprising: at least one satellite in communication with at least oneGlobal Positioning System device providing a first communication linkbetween the at least one satellite to determine a location of at least afirst train; a second communications link allowing communicationsbetween at least one fixed station and at least a first said train;wherein said second communications link provides continualcommunications between said at least one fixed station and at least oneof a potentially unlimited number of other trains; wherein, said firstcommunications link provides a location of any one said trains and saidsecond communications link provides a location of one train relative toat least one other train via processing means in each said at least onetrain; and wherein each fixed transponder-station further emitscorrection signals for correcting errors in Global Positioning Systemsignals from said first communications link to enable determination ofexact track separation of trains on a track network allowing forrespective train lengths and track curvature, the method comprising thesteps of: a) using the first communication link to provide a location ofa first train; b) activating a Global Positioning System radio systemincluding a Global Positioning System interface and a communicationsubsystem; c) placing train track identification means at predeterminedtrack locations to provide signals of track identification to vehicles;d) receiving input data relating to train operation and environmentparameters; e) analyzing said data via a logic associative memory todetermine a collision risk between at least two trains; f) activating anoverride signal responsive to a collision risk in the event that onetrain is on a collision course with another train; g) locating at eachsaid fixed station, transponders on the train track at a known positionand at a predetermined distance from each other; h) allowing eachtransponder to emit a range signal for track identification; and i)allowing the fixed station to emits correction signals for correctingerrors in Global Positioning System ranging signals from said firstcommunications link.
 26. A method according to claim 25 wherein saidcorrection signals allow further correction measurements for improvingthe accuracy of the Global Positioning System ranging signals.
 27. Amethod according to claim 26 comprising the further step ofcommunicating a tracked position of one train for receipt by at leastone other train in real time to allow each said trains to determine adistance of separation from at least one other train.
 28. A methodaccording to claim 27 comprising the further step of providing a centralcontroller for monitoring train locations and capable of transmitting anoverride signal to prevent a collision.
 29. A method according to claim28 comprising the further step of processing positions of each saidtrains received and/or transmitted to each said train via a neuralnetwork.
 30. A method according to claim 29 wherein said neural networkidentifies and evaluates each potential collision hazard of one trainrelative to another train.
 31. A method according to claim 30 comprisingthe further step of allowing transponder range signals to allowdetermination via said neural network in a logic associative memory of afirst train position relative to another train for determination of acollision hazard.
 32. A method according to claim 31 wherein, in theevent of a collision hazard a response control signal is generated foractuating an override control mechanism, which communicates with traincontrols, to stop the trains short of a collision.
 33. A method foroperating a collision warning and avoidance system comprising the stepsof: a) providing a network of satellites capable of continuouscommunications via a first communications link with one or more of aplurality of trains; b) ranging signals for initially accuratelydetermining a train position on a rail track, c) receiving continuouslya signal at each said train via a second communication link from one ofa plurality of transponder stations having a known fixed position on thesurface of the track; d) allowing each fixed transponder station tofurther emit correction signals for correcting errors in GlobalPositioning System signals from said first communications link to enabledetermination of exact track separation of trains on a track networkallowing for respective train lengths and track curvature; and e)determining in a logic associative memory a response which generatescontrol signals, that actuate an override control mechanism, thatinfluences train controls to stop the trains short of a collision in theevent of a detected collision risk.
 34. A method according to claim 32comprising an additional step of real-time logging of traincharacteristics to record the last several minutes of driving action tothereby enable reconstruction of events leading up to a collision.
 35. Amethod according to claim 34 comprising the further step of providing atrain navigation unit which provides remote train control override for atrain controller to stop at least one train in the event of a collisionrisk.
 36. A method of preventing train collisions comprising; a computercontrolled collision avoidance and warning system; the systemcomprising: at least one satellite in communication with at least oneGlobal Positioning System device providing a first communication linkbetween the at least one satellite to determine a location of at least afirst train; a second communications link allowing communicationsbetween at least one fixed transponder station and at least a first saidtrain; wherein said second communications link provides continualcommunications between said at least one fixed transponder station andat least one of a potentially unlimited number of other trains; wherein,said first communications link provides a location of any one saidtrains and said second communications link provides a location of onetrain relative to at least one other train via processing means in eachsaid at least one train; and wherein each fixed transponder stationfurther emits correction signals for correcting errors in GlobalPositioning System signals from said first communications link to enabledetermination of exact track separation of trains on a track networkallowing for respective train lengths and track curvature; the methodcomprising the steps of: a) activating a Global Positioning System radiosystem including a Global Positioning System interface and acommunication subsystem; b) using the first communication link toprovide a location of each one of a plurality of trains; c) placingtrack identification means at predetermined track locations to providesignals of track identification to vehicles; d) receiving at a maincontrol unit input data relating to train operation and environmentparameters e) analyzing said data via a logic associative memory todetermine a collision risk between at least two trains; and f)activating an override signal responsive to a collision risk in theevent that one train is on a collision course with another train.